Kidney Disease Spikes, But Cause Unclear

THURSDAY, May 30, 2013 — Kidney disease is on the rise, and this silent killer now affects more than 10 percent of people worldwide, according to a report published today in the Lancet. Even worse, the disease, which chiefly affects the elderly, is also spreading into the younger population, which experts say is being driven by the obesity epidemic.

Kidney disease is characterized by a reduction in the organ’s ability to filter blood, but the disease can affect far more than just the kidneys, researchers said. It can also lead to other organ failure and even heart disease – and with the prevalence spiking, doctors are now screening for the disease more than ever.

“Even mild forms of kidney disease are associated with various adverse effects on body functions and an increased risk of mortality and cardiovascular morbidity,” the researchers, led by Kai-Uwe Eckardt, MD, a researcher with the University of Erlangen-Nürnberg, wrote in the report. “Genetic causes of specific forms of kidney disease and susceptibility to development of kidney disease in the context of other disorders are also now being increasingly recognized.”

Between 2000 and 2008, kidney disease in people over the age of 65 doubled in the United States, according to the report, but Eli Friedman, MD, a nephrologist and distinguished teaching professor of medicine at SUNY Downstate Medical Center in New York, said the numbers are misleading.

“Older people have less kidney function, but that doesn’t mean they’re diseased,” he said. “For every decade older you get, you lose 10 percent of your kidney function. So a 70 year old may have less kidney function, but that’s normal.”

And while the prevalence of kidney disease is increasing, he added, it’s not nearly as sharp as it seems.

“Kidney disease is increasing, but it’s hard to say how much it’s increasing,” he said.

One of the reasons that kidney disease appears to becoming so widespread is because our life expectancy has increased.

“Life expectancy used to be shorter,” Dr. Friedman said. “Now we’re living longer, and reduced kidney function is just a result of that.”

However, researchers found that kidney disease is even increasing in younger people, with 1 in 25 adults between the ages of 20 and 39 now afflicted with the condition, which they attribute to the increasing rate of obesity and diabetes.

“The increase in obesity has been accompanied by notable increases in hypertension, diabetes, cardio­ vascular disease, and chronic kidney disease,” the researchers wrote. “The association of chronic kidney disease with an increased frequency of obesity is partly because hypertension and diabetes are known causes of kidney disease and failure. “

Researchers said that getting screened is the best way to reduce the rate of kidney disease. It can be diagnosed with a simple blood test, said Brian Radbill, MD, a nephrologist with Mount Sinai Hospital in New York City, so anyone at risk for it, such as those who have diabetes or hypertension, should get tested.

“Catching it early means you can institute strategies to slow the progression,” he said. “It doesn’t mean you will be able to cure it, but you can treat it easier.”